Cross-linked alpha-galactosidase aggregates: optimization, characterization and application in the hydrolysis of raffinose-type oligosaccharides in soymilk

WOS: 000471905200028PubMed ID: 30932192BACKGROUND Cross-linked enzyme aggregates (CLEAs) of alpha-galactosidase, partially purified from maize (Zea mays) flour, were prepared. The impact of various parameters on enzyme activity was examined to optimize the immobilization procedure. Biochemical characterization of the free and immobilized enzyme was carried out. Stability (thermal, pH, storage and operational stability) and reusability tests were performed. The potential use of the free enzyme and the CLEAs in hydrolysis processes of raffinose-type oligosaccharides present in soymilk was investigated. RESULTS alpha-galactosidase CLEAs were prepared with 47% activity recovery under optimum conditions [1:5 (v/v) enzyme solution:saturated ammonium sulfate solution ratio; 7.5 mg protein and 0.1% (v/v) glutaraldehyde, 6 h, 4 degrees C, 150 rpm]. alpha-galactosidase CLEAs exhibited increased stability in comparison to the free enzyme. The CLEAs and the free enzyme showed a maximum activity at 40 degrees C and their optimal pH values were5.5 and 6.0, respectively. Kinetic constants (K-M, V-max and k(cat)) were calculated for the free enzyme and the CLEAs in the presence of p-nitrophenyl-alpha-d-galactopyranoside, stachyose, melibiose and raffinose. The effect of various chemicals and sugars on enzyme activity showed that both enzyme forms were significantly inhibited by HgCl2 and galactose. The CLEAs hydrolyzed 85% of raffinose and 96% of stachyose. CONCLUSION The alpha-galactosidase CLEAs, with their satisfactory enzymatic characteristics, have much potential for use in the food and feed industry. (c) 2019 Society of Chemical IndustryEge University Research FoundationEge University [2013 FEN 022]This work was funded by the Ege University Research Foundation (Project 2013 FEN 022)

Enzymes, 5. Enzymes in Organic Synthesis

The article contains sections titled: 1. Introduction 2. Examples of Enzymatic Conversions 3. Enzyme-Analogous Catalysts 4. Commercial Applications 5. Outloo